21429819 has 16 divisors (see below), whose sum is σ = 31827840. Its totient is φ = 14250600.

The previous prime is 21429817. The next prime is 21429827. The reversal of 21429819 is 91892412.

It is not a de Polignac number, because 21429819 - 2¹ = 21429817 is a prime.

It is a super-2 number, since 2×21429819² = 918474284745522, which contains 22 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21429817) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14044 + ... + 15494.

It is an arithmetic number, because the mean of its divisors is an integer number (1989240).

Almost surely, 2^21429819 is an apocalyptic number.

21429819 is a deficient number, since it is larger than the sum of its proper divisors (10398021).

21429819 is a wasteful number, since it uses less digits than its factorization.

21429819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2007 (or 2001 counting only the distinct ones).

The product of its digits is 10368, while the sum is 36.

The square root of 21429819 is about 4629.2352500170. The cubic root of 21429819 is about 277.7620023693.

The spelling of 21429819 in words is "twenty-one million, four hundred twenty-nine thousand, eight hundred nineteen".